ERGONOMICS DEMONSTRATION PROJECT -...

E R G O N O M I C S D E M O N S T R A T I O N P R O J E C T

Utilities

December, 2002


INTRODUCTION TO UTILITIES DEMONSTRATION PROJECT: The utility industry is very aware that utility workers experience many serious work-related musculoskeletal disorders (WMSDs), particularly affecting the back and shoulders. In1999, four people from several electric utility companies started informal quarterly meetings to discuss common ergonomic issues and ideas to address common problems. Rather than each company having to independently think of ways to solve problems, a group effort seemed to be a wiser approach. They saw the benefits of learning from one another--sharing things each utility had tried, what worked well, and what did not. Word spread and interest in the group rapidly grew, expanding membership to over fifteen western utility companies from five states and British Columbia. The group began calling itself the Western Utilities Ergonomics Group (WUEG). WUEG membership grew to include health and safety personnel from electric, gas, water, and sewer utilities. Since Washington State adopted the ergonomics rule, it prompted the WUEG to learn about the rule and figure out how to apply it to their workforce. WUEG realized the need to do job analyses to identify caution zone jobs and hazard zone jobs. Despite membership outside Washington, the group the group agreed to work together to address the Washington rule. WUEG asked to be involved in a demonstration project. The demonstration project began in April 2001. The group was highly concerned about how to assess jobs with high task variability. The project used a two-prong approach. One part was to encourage appropriate use of the caution zone job/hazard zone job checklist methods for many jobs. The second part was to develop an assessment method intended for more difficult jobs. The full demonstration project will be presented in several sections.

1. Job Assessments

2. Manhole Cover Removal 3. Component Method

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JOB ASSESSMENTS Members of the Western Utilities Ergonomics Group (WUEG) completed 13 assessments of common utility jobs. These assessments came from 8 utility companies including water, gas, sewer, and electric utility companies. All caution zone job assessments were completed using a checklist approach except the lineworker job. Each job was evaluated to see if it met any caution zone criteria. A Hazard level assessment was completed for each noted caution zone job. Hazard zone jobs are listed as HZJs. All identified hazards were due to heavy lifting. (See next page prior to viewing individual job assessments). Click job title to view full assessment. Solution examples are provided for identified hazards.

Summary Results of Job Assessments:

Job Title Type of Utility

Employer Assessment Result

1. Meter Reader Water City of Everett No CZJ 2. Supervisor Water City of Everett No CZJ 3. Meterman Electric Clark Public Utilities No CZJ 4. Lab Assistant Water Seattle Public Utilities CZJ, No HZJ 5. Microbiologist Water Seattle Public Utilities CZJ, No HZJ 6. Chemist Water Seattle Public Utilities CZJ, No HZJ 7. Utility Electrician Electric Mason County PUD CZJ, No HZJ 8. Customer Field

Service Technician Gas Puget Sound Energy

(gas and electric) CZJ, No HZJ

9. Wire Room � Wireman

Electric Seattle City Light HZJ

10. Lineworker Electric Composite assessment from multiple utilities

HZJ

11. Vactor truck operator

Water Woodinville Water District

HZJ

12. Gas Fitter Gas Puget Sound Energy HZJ 13. Maintenance

Worker 2 Sewer City of Vancouver,

WA HZJ

Each company can use these results as a useful comparison, but will need to determine if their own employees have similar exposures. The results of this table reflect the job at a particular utility company. The results may not be true for the same job title at a different utility depending on the mix of job duties per company. Companies are responsible to verify their own results.


** Only Abbreviated descriptions from column 2 will be used in each job assessment

Full Description of Caution Zone Jobs Abbreviated Descriptions of Caution Zone Jobs

1. Hands above the head, or elbow(s) above the shoulder for more than 2 hrs. per day

1. Hand(s) overhead

2. Neck or bent back > 30o for more than 2 hrs. per day (without support and without the ability to vary posture

2. Neck bent > 30o or back bent > 30o

3. Squatting for more than 2 hrs. per day 3. Squatting 4. Kneeling for more than 2 hrs. per day 4. Kneeling 5. Pinching an unsupported object(s)

weighing > 2 lbs. per hand, or pinching with a force of > 4 lbs. per hand, for more than 2 hrs. per day (comparable to pinching half a ream of paper)

5. Pinching > 2 lbs. or > 4 lbs. of force

6. Gripping an unsupported object(s) weighing > 10 lbs. per hand, or gripping with a force > 10 lbs. per hand for more than 2 hrs. per day (comparable to clamping light duty automobile jumper cables onto a battery)

6. Gripping > 10 lbs. or > 10 lbs. of force

7. Repeating the same motion with the neck, shoulders, elbows, wrists, or hands (excluding keying activities) for more than 2 hrs. per day

7. Highly repetitive motions

8. Performing intensive keying more than 4 hrs. per day

8. Highly intensive keying

9. Using the hand (heel/base of palm) or knee as a hammer > 10 times per hour for more than 2 hrs. per day

9. Repeated impact (hand or knee)

10. Lifting objects weighing > 75 lbs. once per day OR > 55 lbs. for more than 10 times per day

10. Heavy lifting

11. Lifting objects weighing > 10 lbs., if done more than twice per minute for more than 2 hrs. per day

11. Frequent lifting

12. Lifting objects weighing > 25 lbs. above the shoulders, below the knees, or at arms length more than 25 lbs.

12. Awkward lifting

13. Using impact wrenches, carpet strippers, chain saw, percussive tools (jack hammer, scalers, riveting or chipping hammers) or other hand tools that typically have high vibration levels more than 30 minutes per day.

13. Using high vibration tools

14. Using grinders, sanders, jigsaws or other hand tools that typically have high vibration levels for more than 2 hrs. per day

14. Using moderate vibration tools

Refer to Appendix B of the Washington State Ergonomics Rule for a full description of the twenty-one risk factors and exposure durations that define hazardous jobs. Each job assessment will detail only applicable HZJs. If only one hazardous risk factor applies, only one will be listed.

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MANHOLE COVER REMOVAL: What Methods are Acceptable?

Sometimes the hook is inserted directly on the rim as is depicted in the picture above.

Current removal method: Manual tools such as a T-hook or a sledge/pry bar are often used to remove manhole covers (lids) to allow access into underground vaults. Generally, the worker inserts the tool into a pick hole and uses a jerking motion to unseat the lid. This portion of the task is the �lifting� portion. Still using the tool, the lid is dragged several inches away from the opening. After the work is completed, the lid is dragged back to the opening and is re-

seated. More commonly a longer tool is inserted in an interior hole, as depicted above. Hand height and posture would change as a result.

Manhole covers differ in size, weight, load bearing ability, and pick hole design pattern. This is true within a single utility as well as when compared to lids from a similar type of utility. They differ even more so when compared to a

different type of utility (for example, electric versus communications or water utilities). Since hole patterns are not uniform, the tool insertion point varies with each lid. The pick hole is generally a few inches away from the rim of the lid. The �lifting� portion is considered a partial lift because the worker does not actually bear the entire load of the lid while unseating it. The ring along the lid�s far rim supports some of the lid weight. Assumption: the pick hole�s distance from the far rim is greater than 3/4 of the diameter of the lid. Depending on the actual pick hole location, the approximate force requirement to unseat the lid will range between ½ to 2/3 of the total weight. To be conservative, use 2/3 of the total weight of the lid as the lifting weight when using the lifting calculator in the Washington State Ergonomics Rule. (When the pick point is on the rim, ½ the total lid weight can be used as the lifting weight.) In the best-case scenario**, the maximum weight a person is allowed to lift is 90 lbs. unless the lifting is so infrequent that it is not covered by the rule.

**NOTE: Best case scenario parameters for lifting�all three conditions must apply: 1) lifts done less than once every 5 min. 2) hands are positioned between the knees and the waist 3) hands are positioned between 0-7� from the toes

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By creating a table that includes size and weight for the commonly used manhole covers per utility, one will know to never attempt the manual removal of specific types of manhole covers. (See sample table on next page). The size/weight of lid will dictate whether or not one person may try to manually remove the manhole cover (for example, lids that weigh < 135 lbs.). A two-person team may attempt manual lid removal for lids that weigh up to 270 lbs. However, if the lid is impacted and does not easily pop out from its ring, a mechanical device should be used. Even though it takes more effort to unseat impacted lids, utility companies are not required to use force gauges to measure this. The Washington State Ergonomics Rule does not ask nor require this type of measurement for hazard determination. Instead, it strictly relies on item weight as an indirect indicator for lifting force. This can be obtained via a scale, specification sheets, etc. Spring-assisted hinges are frequently used on hinged vault lid doors. Utility workers indicate that by comparison these hinges make the lifts much easier and are not likely to require more than 90 lbs. of force. Thus, a 1-person manual lift would be an acceptable lift. (Force measurements were not taken).

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Manhole Cover Weights and Acceptable Lifting Methods

Type of Utility Diameter

Weight 2/3Weight

Acceptable Method

Electric 24� 80 lbs. (Tacoma Power) 53 1-person manual method 2-person manual method or mechanical method

29� 200 lbs. (Tacoma Power) 132 2-person manual method or mechanical method

38.5� 420 lbs. (Tacoma Power) 277 Mechanical method 42� Solid lid�550 lbs. (Seattle City Light) 363 Mechanical method 42� Vented lid--445 lbs. (Seattle City

Light) 294 Mechanical method

30� Solid lid--600 lbs. (Seattle City Light) 396 Mechanical method 24� Solid lid�400 lbs. (Seattle City Light) 264 Mechanical method

3� x 3� grate

165 lbs.�reportedly the spring assisted hinges make it much easier to open.

109 1-person manual method

Water ?? 75-90 lbs (City of Everett) 50-59 1-person manual method

2-person manual method or mechanical method

Spring assisted hinged lid

?? 100 lbs. per side (City of Everett)-- reportedly the spring-assisted hinges make it much easier to open.

66 1-person manual method

Other: grates ?? 35 lbs. (City of Everett) 23 1-person manual method 2-person manual method or mechanical methods

Sewer

24� 145-155 lbs. (City of Vancouver, WA) 96-102 2-person manual method or mechanical method

Communications WUEG does not have any members from communications so does not have this information. The blank row is provided for illustrative purposes. **A mechanical assist device should be used for impacted lids 135 lbs is the maximum lid weight for 1-person manual method 270 lbs. is the maximum lid weight for 2-person manual method

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Examples of mechanical assist devices: These pictures illustrate some examples of devices that may reduce exposure to heavy lifting. Each utility will need to determine which device will be appropriate for their facility. Not every device is designed to lift every type of manhole cover. Some can be used for only a limited range of weight and lid diameter.

Hydraulic hand pump

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COMPONENT METHOD Background: There was strong belief among Western Utilities Ergonomics Group (WUEG) members that utility jobs were difficult to evaluate because it was hard to define a �typical day�. One day of work could be very different from the next day of work. A crew may perform a wide mixture of jobs over the course of a day, a week, or a month. A crew may do the same type of job assignment for a day, followed by 4 days of a different type of job assignment, then followed by a few days with mixed job assignments. WUEG members were frustrated by not knowing what to consider as a typical workday. Field workers also responded the same manner when they were interviewed. This section of the demonstration project gives an overview of the Component Method that was developed and tried on a highly variable job. This document provides results for the first trial use of the component method on the lineworker job. Results of the data provide individual risk factor exposure rates per job component. By knowing the amount of time spent in the broad categories, one can easily determine the exposure time per risk factor. For example, 21% of the total time working in-the-bucket is spent using a forceful grip. Thus five hours of working in-the-bucket means 63 minutes exposure to forceful gripping. Results from the Component Method show that realistically, lineworkers will not reach caution zone status for any risk factor during any given workday consisting of underground work or bucket work. **Exception: Since work sampling is not the best method to use for infrequent events, heavy lifting was evaluated separately. (See the lineworker report for details and complete assessment results). We hoped to find that most jobs could be assessed via the Labor & Industries caution zone checklist method without needing to use the component method. This was confirmed by the end of the project. After seeing the component method results, members became convinced that exposure times were much lower than they originally believed. Thus, they became much more confident to decide whether exposures reached caution and hazard zone levels or not.

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Component Method: Components are mutually exclusive broad categories. For the most part they are based on work location and are limited in number. Examples include in-the-bucket; on-the-pole; underground; site set up/clean up; travel/paperwork or planning; and prep work at home base. Large broad categories are chosen because it is easier to estimate the total time spent in a day while working in a bucket than it is to estimate time spent doing a vast array of tasks and activities (for example,., installing a transformer, using a hotstick, crimping wire, pulling wire, etc). There is so much difficulty distinguishing between activities and tasks that it becomes a futile exercise due to a lack of consistency in terms and an intermixing of level of detail. A Labor & Industries ergonomist proposed using a work sampling method (component method) for the lineworker job. The component method can also be applied to other highly variable jobs. Lineworker activities were first categorized into components. This method of work sampling involved recording the presence of risk factors for a worker at discrete 60-second intervals. Work sampling was done solely from videotaped work, not in real time. Data came from two different components (in-the-bucket and underground work). Five 1-hour data sets were collected for each component. The pooled data was used to determine risk factor exposure rates per job component. Data sets came from different utilities.

A decision was made to collect data for just two work components for the lineworker. WUEG agreed that workers have the greatest exposure to risk factors while working in-the-bucket and while doing underground work. Lineworkers climb poles and work from the pole on such a limited basis that data samples could not be collected for this project. Heavy lifting exposures from other components such as those encountered while loading trucks is accounted for within the lineworker full job assessment.

The following list describes the group process used for learning and completing the component method from start to finish:

• Defined components for the lineworker job • Reviewed the fourteen risk factors that define caution zone jobs • Trained members to record risk factor data using frozen frames from

videotape. Reviewed videotapes and practiced recording information as a group.

• Provided tips for the best ways to videotape the work and suggested conveying some verbal information on the videotape. (Verbal cues can help when there is a brief obstructed view or for scenarios when the camera person stands well below the level of the worker. In such cases it

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is difficult to discern awkward postures simply from a two dimensional image on a videotape.)

• Added other information to the data collection sheet. WUEG wanted to collect additional data on: awkward wrist postures; neck extension; high push/pull force�shoulders; and high push/pull force�whole body.

• Gave out assignments to members: film lineworkers doing work in component 1 (while in-the-bucket)

• Members recorded work sampling information from their 1-hour data set on data sheets

• Reviewed results of preliminary data and when completed, of pooled data (Five 1-hour data sets) for component 1

• Gave out assignments to members: film lineworkers doing work while doing work in component 2 (underground work)

• Reviewed results of pooled data (Five 1-hour data sets) for component 2 • Discussed the meaning of the results and how to apply the results with the

group • As a group, completed a caution zone job assessment and hazard level

assessment for the lineworker job. Specifically discussed all items the group knew to be lifting hazards. Listed the weights and potential hand positions for the lifts. Discussed ways to reduce the hazardous exposures.

See lineworker full job assessment.

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RESULTS: Sampling Data for Two Components

Component 1

Lineworkers: In-the-Bucket

n=295

Component 2Lineworkers:

Underground work n=297

Risk Factors (short description only)

Frequency % of Samples Frequency % of Samples

0. No exposure 151 51% 67 23% 1. Hand(s)overhead 49 17% 11 4%2. Neck bent 30 10% 66 22% 3. Back bent >30o 25 (+3) 9% 42 (+ 45) 29% 4. Back bent >45o 3 1% 45 15% 5. Squatting 0 0% 37 12% 6. Kneeling 0 0% 66 22% 7. Pinch >2# or 4# force 13 4% 24 8%8. Grip>10# 61 21% 95 32% 9. Repetitive motion every few secs 23 8% 30 10%10. Awkward wrist (F30; E45; UD30) 5 2% 37 12% 11. Intensive keying 0 0% 0 0%12. Repeated impacts (hand or knee) 0 0% 0 0%13. Lifting (must be >10 #) 18 6% 6 2%14. Moderate vibration tool 0 0% 1 0%15. High vibration tool 0 0% 0 0%201. Neck extension 28 9% 7 2%202. High push/pull force�shoulders 6 2% 6 2%203. High push/pull force--whole body 0 0% 2 1%

Shaded cells are those with percentages > 10%

NOTE: Heavy lifting is not well suited for work sampling methods because it happens on an infrequent basis. Lifting will be addressed by other means using known weights of items. ALSO: Awkward wrist exposures are likely to be underestimated. Videotaped work periods could not include wrist postures of workers all of the time. Awkward wrist postures were counted as exposures only when awkward wrist position was actually observed in the video at the sampling interval or if there was strong likelihood based on similar, yet non-obstructed views observed on the videotape.

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Interpretation of Sampling Data: While the lineworker performs duties in-the-bucket�

o 21% of the time the worker used a forceful grip (> 10 lbs. of force or holding item >10 lbs)

o 17% of the time the worker had his/her hand(s)

overhead or elbow(s) above shoulder height -----------------------------------------------------------------------------

o 51% of the time the worker had no exposure to risk factors

While the lineworker performs duties in underground work�

o 32% of the time the worker used a forceful grip (> 10 lbs. of force or holding item >10 lbs)

o 29% of the time the worker had a bent back > 30o

o 23% of the time the worker had no exposure to risk

factors

o 22% of the time the worker had a bent neck posture

o 22% of the time the worker was kneeling

o 15% of the time the worker had a bent back > 45o

o 12% of the time the worker was squatting

o 12% of the time the worker had awkward wrists -------------------------------------------------------------------------------------

o 23% of the time the worker had no exposure to risk factors

The percentage of samples value (for the pooled data set) can be used for an exposure rate. Use the percentage as a multiplier to determine risk factor exposure time Example:

= X

Multiplier for gripping Amount of time doing work in component 1

Amount of gripping exposure for component 1

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Interpretation (continued): Example for in-the-bucket--component 1:

Risk Factor

Exposure Time

Not exposed to risk factors 153 mins Hand(s) overhead or elbow(s) above shoulder height

51 mins

If a worker spends 5 hrs a day doing

in-the-bucket work

Forceful grip > 10 # of force 63 mins Example for underground work--component 2:

Risk Factor

Exposure Time

Forceful grip > 10 # of force 58 mins Bent back >30o 52 mins Not exposed to risk factors 41 mins Bent neck >30o 40 mins kneeling 40 mins Bent back >45o 27 mins Squatting 22 mins Awkward wrist posture 22 mins

If a worker spends 3 hrs a day doing

underground work

Not exposed to risk factors 14 mins ! If you know the duration for all of the components of the workday, you can

add the parts together to determine the worker�s whole-day exposure to a risk factor.

To illustrate using the durations from examples 1 plus 2:

=XMultiplier for gripping

(0.21) Amount of time doing work in a component 1

Amount of gripping exposure component 1

=XMultiplier for gripping

(0.32) Amount of time doing

work in a component 2 Amount of gripping

exposure component 2

(300 mins) x (0.21) = 63 mins forceful gripping in component 1

+ (180 mins) x (0.32) = 58 mins forceful gripping in component 2 ________________________________________________________ 121 mins forceful gripping for both components If these durations accurately reflect a typical workday, this job would be a caution zone job (CZJ) because of forceful gripping, but would not be a hazard zone job (HZJ).

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Interpretation (continued): On the other hand, if a worker is limited to doing work in a single component� For in-the-bucket work:

Risk Factor Component time

threshold to be a CZJ

To reach the hazard level of exposure by doing in-the-bucket work�

Forceful gripping

>9 hrs and 32 mins

Excessively high and improbable�N/A

Hand(s) overhead or elbow(s) above shoulder level

>11 hrs and 46 mins

Excessively high and improbable�N/A

For underground work:

Risk Factor Component time

threshold to be a CZJ

To reach the hazard level of exposure by doing underground work�

(these are also excessive and highly improbable but are provided for

illustrative purposes)

Forceful gripping

>6 hrs and 15 mins

If forceful gripping only�>12 hrs and 30 mins If combined with high repetition. > 9 hrs and 22 mins If combined with awkward wrist posture...> 9 hrs and 22 mins If combined with high repetition + awkward wrist posture... >6 hrs and 15 mins

Bent back > 30o >6 hrs and 54 mins

> 13 hrs and 48 mins

Bent neck

>9 hrs and 15 mins

(bent >30o)

Must be a 45o neck bend and > 18 hrs and 11 mins

Kneeling

>9 hrs and 15 mins

> 18 hrs and 11 mins

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Meter Reader Water City of Everett Job Title Type of utility Company Name

CAUTION ZONE JOB CHECKLIST

Abbreviated Descriptions of

Caution Zone Jobs

Can Reach Caution Zone Exposure

Level?

Tasks/Activities That Contribute to Caution Level Exposure

1. Hand(s) overhead NO

2. Neck bent > 30o or back bent > 30o NO

3. Squatting NO

4. Kneeling NO

5. Pinching > 2 lbs. or > 4 lbs. of force NO

Holds a handheld data-logger (2.5 lbs) for approx. 3 hrs./day. Uses an intermediate grip between a pinch and a fist grip. Generally, it rests on the palm and force is not continuously applied. Does not reach 2 hrs. of gripping or pinching. There is a hand strap that keeps the data-logger snug to the hand. Neck straps can also minimize the total grip time.

6. Gripping > 10 lbs. or > 10 lbs. of force NO

7. Highly repetitive motions NO

8. Highly intensive keying NO

9. Repeated impact (hand or knee) NO

10. Heavy lifting NO

11. Frequent lifting NO

12. Awkward lifting NO

13. Using high vibration tools NO

14. Using moderate vibration tools NO

Short description of job duties: Opens in-ground meter boxes to view meter dial and enters information into handheld data-logger. Drives or walks to each location.

Each company can use these results as a useful comparison, but will need to determine if their own employees have similar exposures. The results of this assessment reflects the job at a particular utility. The results may not be true for the same job title at a different utility.

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HAZARD LEVEL ASSESSMENT Discussion: The Meter Reader position does not include caution zone jobs; therefore, the job is not covered by the rule. NOTE: The work process will be changing soon. By the end of 2002, Water Meter Readers for the City of Everett will be driving past the meter to pick up radio signaled information rather than manually opening the vault lids to read the meters. Exposure to risk factors are likely to be even less than the current levels of exposure. Other employers may use this assessment as a useful comparison, but will need to determine if their own employees have similar exposures. As an example, the worker for a different employer may perform additional duties that contribute to the exposure but are not accounted for in the list of contributing exposure task/ activities provided in this assessment. That employer needs to do its own analysis.

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Supervisor Water City of Everett Job Title Type of utility Company Name



Caution Zone Jobs


Level?




3. Squatting NO

4. Kneeling NO







NOTE: Manhole covers weigh up to 90 lbs. however, lid removal does not meet the caution zone criteria because the agreed upon calculated partial-lift weight is 60 lbs. Also, this utility already uses 2 people for lid removal or uses a mechanical assist device. These methods reduce the exposure to heavy lifting so that it does not become a caution zone job.





Short description of job duties: Visits crews in the field to direct work. Field visits can include inspection of vaults and manhole cover removal.


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HAZARD LEVEL ASSESSMENT Discussion: The supervisor position does not include caution zone jobs; therefore, the job is not covered by the rule. Other employers may use this assessment as a useful comparison, but will need to determine if their own employees have similar exposures. As an example, the worker for a different employer may perform additional duties that contribute to the exposure but are not accounted for in the list of contributing exposure task/ activities provided in this assessment. That employer needs to do its own analysis.

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Meterman � Meter & Relay Tech. Electric Clark Public Utilities Job Title Type of utility Company Name

Short description of job duties: Installs, tests, adjusts, and repairs or replaces electric meters anddevices. Installs wiring to related equipment.


Abbreviated

Descriptions of Caution Zone Jobs


Level?




3. Squatting NO

4. Kneeling NO












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HAZARD LEVEL ASSESSMENT Discussion: The Meterman position does not include caution zone jobs; therefore, the job is not covered by the rule. Other employers may use this assessment as a useful comparison, but will need to determine if their own employees have similar exposures. As an example, the worker for a different employer may perform additional duties that contribute to the exposure but are not accounted for in the list of contributing exposure task/ activities provided in this assessment. That employer needs to do its own analysis.

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Laboratory Assistant Water Seattle Public Utilities Job Title Type of utility Company Name



Caution Zone Jobs


Level?



2. Neck bent > 30o or back bent > 30o YES

Washing containers in the sink, other counter work tasks

3. Squatting NO

4. Kneeling NO











Short description of job duties: Collects distribution system drinking water samples along assigned routes and performs field measurements for temperature, chlorine residual and pH. Downloads route information to a hand-held computer before leaving on the route. Uploads the field information from the hand-held computer to the laboratory LIMS system, resolves any problems, and delivers samples to appropriate laboratory for analysis when returning. Performs reservoir patrol function to ensure security has not been breached, to check for any water quality problems, and to collect data on observations about bird populations. Provides support to the laboratory by cleaning and autoclaving glassware, maintaining stocks of clean and labeled sample bottles, and assisting analysts with media and stock preparation.


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HAZARD LEVEL ASSESSMENT Discussion: No hazard level of exposure was reached in this job. Thus there are no requirements to change the job or reduce the exposure levels. However, ergonomics awareness education must be provided to the Laboratory Assistants and their supervisors because the job is a caution zone job. Other employers may use this job assessment as a useful comparison, but will need to determine if their own employees have similar exposures. As an example, the worker for a different employer may perform additional duties that contribute to the exposure but are not accounted for in the list of contributing exposure task/ activities provided in this assessment. That employer needs to do its own analysis.

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Microbiologist Water Seattle Public Utilities Job Title Type of utility Company Name



Caution Zone Jobs


Level?



2. Neck bent > 30o or back bent > 30o YES

Neck bent during a combination of all counter work

3. Squatting NO

4. Kneeling NO



7. Highly repetitive motions YES

HPC shaking and pipeting, capping and uncapping bottles, and using tweezers








Short description of job duties: Provides journey level analytical services to help ensure the water quality of the distribution system. Conducts microbiological analyses for total and fecal coliform, Pseudomonas, fecal streptococci and heterotrophic plate counts (HPC) in treated distribution water, raw source waters and reservoirs using membrane filtration, multiple-tube fermentation, presence/absence tests and pour plates to meet state and federal water quality regulations. Measures chlorine concentrations, water temperature, and pH and performs other field tests. Enters data and generate reports. Analyzes test results. Provides expertise to assist in the design of special studies to evaluate the impacts of treatment or regulatory changes.


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HAZARD LEVEL ASSESSMENT

Discussion: No hazard level of exposure was reached in this job. Thus there are no requirements to change the job or reduce the exposure levels. However, ergonomics awareness education must be provided to the Microbiologists and their supervisors. Other employers may use this assessment as a useful comparison, but will need to determine if their own employees have similar exposures. As an example, the worker for a different employer may perform additional duties that contribute to the exposure but are not accounted for in the list of contributing exposure task/ activities provided in this assessment. That employer needs to do its own analysis.

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Chemist Water Seattle Public Utilities Job Title Type of utility Company Name



Caution Zone Jobs


Level?


1. Hand(s) overhead MAYBE Phase removal pipetting under the laminar flow hood


3. Squatting NO

4. Kneeling NO











Short description of job duties: Plans, schedules and coordinates work in the Chemistry lab to ensure timely and accurate compliance with drinking water regulations. Evaluates analytical results and associated QC to ensure data accuracy and precision. Performs specialized chemical analyses of drinking water, including organics, metals and conventional chemistry. Train analysts and senior lab assistants in the chemical analysis of drinking water. Plans and conducts special water quality studies to support drinking water treatment and operations. Operates laboratory instruments such as gas chromatograph, TOC analyzer, Rapid Flow Analyzer for nutrients, UV spectrophotometer, GFAA analyzer for trace metals, pH meter, etc. Uses lab equipment such as balance, pipette, titration equipment, etc.


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Discussion: Although there is the possibility of reaching two hours of exposure for hands overhead or elbow(s) above the shoulder, the worker certainly would not reach the hazard level of exposure in this job. Thus, there are no requirements to change the job or reduce the exposure levels. However, ergonomics awareness education must be provided to the Chemists and their supervisors unless the employer reasonably determines that they are not in the caution zone. Other employers may use this job assessment as a useful comparison, but will need to determine if their own employees have similar exposures. As an example, the worker for a different employer may perform additional duties that contribute to the exposure but are not accounted for in the list of contributing exposure task/ activities provided in this assessment. That employer needs to do its own analysis.

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Utility Electrician Electric Mason County PUD Job Title Type of utility Company Name

Short description of job duties: Performs electrical work for utility including: emergency repair of customer underground secondary faults; emergency repair of customer service up to and including main panel; splices, tests, and maintains fiber optic lines.


Abbreviated



Level?




3. Squatting NO

4. Kneeling NO

5. Pinching > 2 lbs. or > 4 lbs. of force YES

Using hand tools (screw drivers and tools for splicing fiber optics)











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Discussion: No hazard level of exposure was reached in this job. Thus there are no requirements to change the job or reduce the exposure levels. However, ergonomics awareness education must be provided to the Utility Electricians and their supervisors. Other employers may use this assessment as a useful comparison, but will need to determine if their own employees have similar exposures. As an example, the worker for a different employer may perform additional duties that contribute to the exposure but are not accounted for in the list of contributing exposure task/ activities provided in this assessment. That employer needs to do its own analysis.

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Vactor Truck Operator Water district Woodinville Water District Job Title Type of utility Company Name



Caution Zone Jobs


Level?



2. Neck bent > 30o or back bent > 30o

MAYBE (only during annual

maintenance projects)

Looking into the sewer hole and when guiding the hose reel.

3. Squatting NO

4. Kneeling NO



These operators use a foot control to operate the hose reel controls during jetting. This eliminates gripping a handheld control. These operators use a trigger lock on the water gun so that they do not constantly grip the trigger.




10. Heavy lifting YES Manhole covers�depends on lid weight





Short description of job duties: Jet sewer lines using a high-power nozzle and water line attached to a Vactor truck. Spray debris with water gun during jetting. Use a suction tube to extract excess water in plugged lines or excavation ditches. Suck out dirt from excavation site. Each task involves handling equipment or operating controls. Other duties involve scheduling activities, driving to the locations, set up and various other duties.


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A. Lifting Hazard(s): Yes

Table itemizes all lifts that called for the hazard level of assessment NOTE: If the same item is lifted from different positions, two or more hand zone numbers appear in the Hand Zone cell (e.g., lifting from ground level and lifting off the truck bed).

Item Lifted

Weight (in lbs.)

Frequency

Factor

Twist Factor

Hand Zone(s)

(Use number from lifting calculator

picture)

Is it a Hazard?

1. Manhole covers (lids) using traditional manual method

Variable- Up to 155

1 1 90

YES

(depends on lid weight)

B. Hazard due to Back Bent >30o for > 4 hrs. per day OR Back Bent >45o for > 2 hrs. per day: To be determined.

For most days of the year, the durations do not even reach caution zone job levels of exposure. For the limited 2-week period of each summer that the crew does intensive jetting tasks, exposures most likely will reach CZJ levels and perhaps HZJ levels of exposure for bent back. An assessment that considers this period of concentrated work activities will need to be done. (This may be better evaluated during the annual maintenance period when activities can be observed or be freshly recalled.)

HAZARD REDUCTION EXAMPLES

Lifting Manhole covers: See separate section on manhole cover removal for further details. Recommendations: one person may use the traditional manual method for removing lids weighing up to 135 lbs. Likewise, two people can use the traditional manual method for lids weighing up to 270 lbs. All lids outside of those weight ranges require a mechanical assist. Some examples include wheeled and non-wheeled lid extractor devices, truck mounted cranes, and truck booms with a winch. Some tools incorporate leverage so that the user pushes down on the tool handle rather than lifting it

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or pulling up on it. Lightweight manhole covers made from composite materials can also be used for some applications. A mechanical assist should be used for all impacted lids due to the increased difficulty to unseat these lids.

Potential Hazard for neck/back bent: Operators try to keep the water line hose centered through the manhole while guiding the hose and hose reel. They often stand with awkward postures in order to maintain the optimum hose placement in the hole. Recommendations: 1) A possible way to reduce neck/back bending is to mount an extension to the handle of the hose reel guide. By using a longer handle, the worker would not need to lean forward to manage the hose reel guide. 2) Job rotation can be used so that workers switch job tasks with one another, splitting the total exposure time between the two workers.

EXPOSURE REDUCTION EXAMPLES ALREADY AT WORK

Gripping hose reel remote control device: Operators use foot pedals instead of hand controls to control the water line hose in the sewer access port (SAP).

Gripping trigger of water gun: Operators use a trigger lock to hold the trigger in the open position to alleviate the need for a constant grip.

Discussion: This employer is responsible for: • Ergonomics awareness education for Vactor Truck Operators and their

supervisors • Reducing the hazardous lifting exposures to below the hazard level • Annual review of caution zone jobs • Determining if risk factor exposures during the concentrated annual

maintenance activities are hazardous. Address hazards if present. Employees must be involved in hazard assessment and when selecting measures to reduce WMSD hazards. Other employers may use results of this job assessment as a useful comparison, but will need to determine if their own employees have similar exposures. For example, the worker for a different employer may perform additional duties that contribute to the exposure but are not accounted for in the list of contributing exposure task/activities provided in this assessment, that employer needs to do its own analysis.

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Wire Room � Wireman Electric Seattle City Light Job Title Type of utility Company Name



Caution Zone Jobs


Level?




3. Squatting NO

4. Kneeling NO






10. Heavy lifting YES Coils of pre-cut wire; lifting coils of wire on/off the coiling machine or hand truck; making hand coils or placing them in stock.





Short description of job duties: Takes requests for specific wire from Line Crew/Underground Crew. For precut wire, will locate coil in warehouse and deliver it to the appropriate dock. If wire is special order or is out of stock, will locate appropriate reel and move it to the measuring/ cutting area. Will mount reel onto rack; pull wire through meter and onto wire coiler; and cut to desired length using pneumatic cutter or hand cutter. Transports items with a hand truck, wire truck or forklift. May roll wire coil from point to point, rather than using mechanical means.


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Lifting Hazard(s): Yes Table itemizes all lifts that called for the hazard level of assessment NOTE: If the same item is lifted from different positions, two or more hand zone numbers appear in the Hand Zone cell (e.g., lifting from ground level and lifting off the truck bed).

Item Lifted

Weight (in lbs.)

Frequency

Factor

Twist Factor

Hand Zone(s)


picture)

Is it a Hazard?

90 NO Most are <78 lbs.

70

YES if coil weighs

> 70 lbs.

90 YES wire coils but did

find a 108 lb.

and 132 lb. coil

1 1

70 YES

HAZARD REDUCTION EXAMPLES Handling wire coils: Recommendations: 1) Store heavier coils of wire (weighing >70 lbs.) standing upright in floor level storage areas. Lighter wire can be stored in the higher 2nd level storage areas. 2) Roll the wire coils instead of lifting them. This includes rolling wire coils into and out of the storage areas when it is possible. 3) If the wire coil is positioned horizontally on a surface, tip the coil to stand it upright rather than lifting it, so that it can be rolled. 4) Use hand trucks to transport coils of wire. 5) For heavy coils, use 2 people to lift the coil or use a mechanical assist such as a forklift. 6) Limit lengths for hand coils so that they weigh less than 90 lbs. For exceptional jobs that require longer, heavier sections of wire, the hand coils will be handled by 2 people or by mechanical means.

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Discussion: This employer is responsible for: • Ergonomics awareness education for Wire Room � Wireman and their

supervisors • Reducing the hazardous lifting exposures to below the hazard level • Annual review of caution zone jobs Employees must be involved in hazard assessment and when selecting measures to reduce WMSD hazards. Other employers may use this assessment as a useful comparison, but will need to determine if their own employees have similar exposures. As an example, the worker for a different employer may perform additional duties that contribute to the exposure but are not accounted for in the list of contributing exposure task/ activities provided in this assessment. That employer needs to do its own analysis.

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Lineworker Electric From pooled data of several electric utilities

Job Title Type of utility Company Name

Short description of job duties: Lineworkers are responsible for maintaining power lines in good and safe condition. General tasks include installing new overhead and underground services, removing old services or hardware, and maintaining existing services. This includes installation/removal of items such as: transformers, wire, insulators, poles, crossarms, etc.



Caution Zone Jobs


Level?


Hand(s) overhead NO

Neck bent > 30o or back bent > 30o NO

Squatting NO

Kneeling NO

Pinching > 2 lbs. or > 4 lbs. of force NO

Gripping > 10 lbs. or > 10 lbs. of force NO

Highly repetitive motions NO

Highly intensive keying NO


2. Heavy lifting YES

Crossarms, feeder arms, compacter, string of bells, hand coil wire, guy wire, triple helix swamp anchor, 7 foot anchored rods, pole trailer tongues, manhole covers.





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NOTE: Although not covered by the Washington State Ergonomics rule, WUEG indicates lineworkers generate very high muscle forces in shoulder girdle muscles when they use manual cutting and compression tools. WUEG believes these are also likely to contribute to the WMSD risk.


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A. Lifting Hazard(s): Yes

Table itemizes all lifts that called for the hazard level of assessment NOTE: If the same item is lifted from different positions, two or more hand zone numbers appear in the Hand Zone cell (e.g., lifting from ground level and lifting off the truck bed).

Item Lifted

Weight (in lbs.)

Frequency

Factor

Twist Factor

Hand Zone(s)


picture)

Is it a Hazard?

1. Crossarm or feeder arm 34-80 1 1 90 NO

70 YES 2. Pole trailer tongue

Approx. 100-150 1 1

90 YES 90 YES

3. Compacter 139 1 1 50 YES

4. String of bells 84 1 1 70 YES

90 YES 70 YES 5. Wire (hand coil) Heaviest

wt.=100 1 .85 65 YES

6. Guy wire factory 3/8� and 7/16�

Heaviest wt.=140 and 200

1 .85 90 YES

90 YES 7. Triple helix swamp anchor 85 1 .85

70 NO 8. 7 ft. anchored

rod 55 1 .85 90 NO

9. Manhole covers (lids)

Variable: up to

600 lbs. 1 1 90 MOSTLY - YES

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HAZARD REDUCTION EXAMPLES ⇒

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Pole trailer tongue (item 2): The pole tongue is an attachment used at the end of a pole. It provides a way to tow a pole to a job site. It is attached after the pole is placed, balanced, and is secured on a trailer. The pole itself then becomes what is called the tongue of the trailer. Recommendation: Use 2 people to attach the pole trailer tongue to the hitch. Also, ensure that the pole is positioned on the trailer so as to balance the load with just enough tongue weight to offer the best trailer handling while being towed, and to minimize the force required to lift/maneuver the pole tongue by hand onto the hitch of the towing vehicle.

Compacter (item 3): Recommendation: For most scenarios the hazard is effectively reduced if two people lift the compacter. For the scenario that sometimes occurs when the compactor is in the trench, but needs to be lifted up out from the bottom of a 2-3 foot trench, the two-person lift is NOT OK. Instead use a mechanical assist such as tying a line from a truck winch to lift the compacter out of the trench.

String of bells (item 4): Lineworkers may work with strings of bells while working from a bucket in the air or while still on ground level (before going up in the bucket). The bells generally come in strings of six bells. The lifting/ handling exposures occur when the lineworker is on ground level in instances such as: loading/unloading the truck, removing them from the packing carton, and lifting and supporting them while attaching the hook to an eyebolt. Recommendation: For lifts that are other than near to the body and between knee and waist height, use two people to lift the string of bells. Other ways to reduce the hazard is to have the manufacturer reduce the number of bells on the string or to substitute the string of bells with a lighter item such as an epoxilator.

Hand coiled wire and (3/8� and 7/16�) guy wire (items 5 and 6): Recommendations: 1) When the wire is unused and still heavy (over 90 lbs.), use 2 people to lift the coil or use a mechanical assist such as the truck boom with a winch or a man-hoist adaptation device to lift the coil of wire. 2) Workers can cut smaller sections of the wire off as needed instead of handling the whole coil. 3) Have the warehouse worker or wire supply company limit hand coil weight to 90 lbs. or less. For exceptional jobs that require longer, heavier sections of wire, the hand coils will be handled by 2 people or by mechanical means.

Triple helix swamp anchor (item 7): Recommendation: Based on the common hand positions when lifting this item, it is hazardous when it is lifted from below the knees or between waist and shoulder height (Hand Zone 70). Use two people to lift this if lifting from these areas.

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Manhole covers (item 9): See section on manhole cover removal for further details. Recommendations: one person may use the traditional manual method for removing lids weighing up to 135 lbs. Likewise, two people can use the traditional manual method for lids weighing up to 270 lbs. All lids outside of those weight ranges require a mechanical assist. A mechanical assist should be used for all impacted lids due to the increased difficulty to unseat these lids. Some examples include wheeled and non-wheeled lid extractor devices, truck mounted cranes, and truck booms with a winch. Some tools incorporate leverage so that the user pushes down on the tool handle rather than lifting with it. Lightweight manhole covers made from composite materials can also be used for some applications.

Discussion: This employer is responsible for: • Ergonomics awareness education for Lineworkers and their supervisors • Reducing the hazardous lifting exposures to below the hazard level • Annual review of caution zone jobs Employees must be involved in hazard assessment and when selecting measures to reduce WMSD hazards. Other employers may use this assessment as a useful comparison, but will need to determine if their own employees have similar exposures. As an example, the worker for a different employer may perform additional duties that contribute to the exposure but are not accounted for in the list of contributing exposure task/ activities provided in this assessment. That employer needs to do its own analysis.

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manhole cover remova

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Customer Field Service Tech Gas (also electric) Puget Sound Energy Job Title Type of utility Company Name

Short description of job duties: Installation, repair and adjustment of appliances, meter work, etc. Identifies, pinpoints and classifies gas leaks; repairs damaged service lines; takes odorant tests and reports results. The position generally involves frequent sitting, standing, walking, bending, reaching, kneeling, twisting, balancing, and climbing.


Abbreviated



Level?




3. Squatting NO

4. Kneeling YES Repairing broken gas lines and customer gas equipment and appliances.












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Discussion: No hazard level of exposure was reached in this job. Thus there are no requirements to change the job or reduce the exposure levels. However, ergonomics awareness education must be provided to the Customer Field Service Techs and their supervisors. Other employers may use this job assessment as a useful comparison, but will need to determine if their own employees have similar exposures. As an example, the worker for a different employer may perform additional duties that contribute to the exposure but are not accounted for in the list of contributing exposure task/ activities provided in this assessment. That employer needs to do its own analysis.

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Gas Fitter Gas (also

electric) Puget Sound Energy Job Title Type of utility Company Name

Short description of job duties: Constructs, installs, maintains, inspects and operates gas-piping systems. Job position primarily handles the first response to leaks and performs repair. Construction aspects of the job are now contracted out. Activities generally involve occasional sitting, frequent standing, frequent walking, moderate to heavy lifting, moderate carrying, frequent bending, reaching, kneeling, twisting, balancing, and climbing.



Caution Zone Jobs


Level?




3. Squatting NO

4. Kneeling YES Repairing broken gas lines






10. Heavy lifting YES Lifting jackhammer from awkward positions in/out of the truck and while using it. Unfolding the truck lift gate.



13. Using high vibration tools YES

Jackhammer, air shovel, and rock drill





A. Lifting Hazard(s): Yes�see all �YES� listings in table Table itemizes all lifts that called for the hazard level of assessment NOTE: If the same item is lifted from different positions, two or more hand zone numbers appear in the Hand Zone cell (e.g., lifting from ground level and lifting off the truck bed).

Item Lifted

Weight (in lbs.)

Frequency

Factor

Twist Factor

Hand Zone(s)


picture)

Is it a Hazard?

50 YES 1. Jackhammer (without tip) 86 1 1

90 NO 2. Jackhammer

(with tip) 94 1 1 90 YES

3. Jackhammer (with tip) 94 0.3 1 90 YES

50 YES 4. Truck lift gate

73 *see

below 1 1

70 YES *Optional Information: The Gas Fitter has to manually unfold and position the lift gate on the back of the truck so that it can be used. It is attached with a hinge and has a spring to make it easier to manually lift. In this case the worker does not completely lift the total weight of the item as is true with a pure �lift�. This type of lift would be considered a partial lift. Even though the weight is not known the employer provided other information that is not required by the Ergonomics Rule. The employer provided the force that is needed to unfold and position the lift gate for use. A force gauge was used to take these measurements. These force measurements are used in the table instead of weight. The employer identified lift gate handling as a problem that they needed to address.

HAZARD REDUCTION EXAMPLES FOR LIFTING

Lifting jackhammers (items1-3): Lifting the 89 lb. jackhammer out of the truck is not a WMSD hazard but would be if the combined jackhammer and chisel weight exceeds 90 lbs. Commonly, a worker tips the jackhammer from ground level to an upright position. Thus, the lifting weight from ground level is at maximum ½ of the total weight of the jackhammer. Once in the upright

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43


position, the worker lifts the jackhammer by the handles from about waist height. Tipping the jackhammer up from the ground is not a lifting hazard. However, a WMSD hazard exists with frequent lifting of the heavy tool during normal operation of a jackhammer. See discussion section for further details.

Recommendations: 1) Use a machine mounted hydraulic pavement breaker (on a backhoe, excavator, etc.) whenever possible. Doing so eliminates heavy lifts and hand-arm vibration exposure related to jackhammer use. 2) Use a walk-behind concrete saw to score and cut the designated area instead of using a jackhammer. Positioning this device does not involve lifting. 3) Use two people when lifting jackhammers that weigh more than 90 lbs. during equipment loading and unloading.

The following recommendations reduce lifting exposures but do not reduce exposures below the hazard level. 4) If manual jackhammering must be done, limit its use to less than 1 hr. per day and use job rotation to keep exposures below this level. 5) If a jackhammer must be used, store the jackhammer in easy to reach locations such as in a holster mounted at an angle on the compressor; storing it in an external cabinet with a low floor and a swing away door so that that it does not have to be lifted over an obstruction; or use a hinge-mounted rod or a bracket that allows the jackhammer to be tilted between horizontal to vertical positions for better positioning while loading or unloading.

Courtesy of Ira Janowitz UC San Francisco/Berkeley

Ergonomics Program

Puget Sound Energy started installing lower racks for the jackhammers. The Gas Fitter leans the jackhammer into a bracket, then rotates it up on end to load it into the truck.

Lift gate handling (item 4): This recommendation is the solution that the employer developed and already implemented: Install a stronger spring to the lift gate.

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Puget Sound Energy contacted the lift gate manufacturer and inquired about changing the spring. The manufacturer sent larger springs to replace the original springs. The lifting force requirement was reduced from 73 lbs. to 30 lbs. Crewmembers are pleased that the lift gates are much easier to manage.

(CONTINUE TO NEXT PAGE FOR JACKHAMMER DISCUSSION)

44


Discussion

Jackhammer Operation � Frequent Lifting of Heavy Jackhammers Utility industry assumptions: 1. Workers use jackhammers for less than 1 hr. per day 2. Hydraulic machine mounted breakers are used for large jobs and when space

affords their use. Situations remain where manual 60 lb. and 90 lb. jackhammers must be used. The maximum acceptable lifting weight is 27 lbs for the given parameters of less than 1 hr. per day, 10+ lifts per minute, and hand location close to the body between knee and waist height. This is a hazardous exposure for either jackhammer. This is still true even if the lift frequency is 8-9 per minute.

Possible options: o Explore the feasibility of using a small walk-

behind mechanical device with a hydraulic breaker attachment. Consider renting a walk-behind device with a hydraulic breaker attachment on a trial basis to determine if this is an appropriate alternative to a manual jackhammer.

o Explore the feasibility of using a rock drill

combined with a hydraulic splitter as an alternative to a manual jackhammer. The method involves drilling a series of holes along the desired cracking line and placing a splitter tool in the hole. Subsequently, the pressure build-up causes the concrete or asphalt to split along the series of holes.

o A prototype of a jackhammer lift-assist device has been made. Currently,

field tests are being conducted on it as part of a gas utility funded project (NYGAS Millennium Project M-2001-011). This is the second-generation prototype. The device is designed to push the embedded jackhammer chisel out of the concrete using an actuator. The operator mainly uses his/her hands to guide and stabilize the jackhammer rather than lift the tool, as before. The primary reason the device was designed was to reduce the force required to unseat a stuck jackhammer chisel. Coincidentally it will also address the frequent lifting problem that leads to the WMSD hazard. (NOTE: The combined weight of the jackhammer plus the device makes it heavier, however, the operator is no longer required to lift the jackhammer to reposition it during normal operation. Workers will still need to lift the jackhammer while loading it on/off the truck). The device is not available commercially at this time. Should this

45


lift-assist device become available in the future, it may effectively reduce the lifting exposure to below the hazard level. (The device was designed by Stu Senator of Dunton Design Associates, Inc.: http//dunton.senator.net)

o A third generation prototype, �RAPTOR III�, was developed to break up

pavement quietly and efficiently (Department of Energy and Brookhaven National Laboratory). The device uses a helium driven gas gun to fire a series of nails into the pavement/concrete. Raptor III is bulky and slower than a jackhammer. It would require further improvements before it could become a viable alternative. This device is not available commercially at this time.

While current practices will continue to be used, employers using this type of equipment should periodically review the availability of feasible alternatives that will reduce the lifting hazards associated with these tools.

B. Exposure to Moderate to High Hand-Arm Vibration: Likely hazard Hazard determination is based on the vibration level of each specific tool (make and model) and the length of time the tool is used. Those numbers are plotted as coordinates into the Hand-Arm Vibration graph (Appendix B of the WA Ergonomics Rule) to determine if a vibration hazard exists.

Vibrating Hand Tool

Make/Model #

Vibration Level

Duration Is it a Hazard?

Jack hammer Thor Model 125 Not Found 1 hr. Likely

Air shovel (chipping hammer with clay spade)

Brand unknown Model OA143 Not Found 30 min. Unable to

determine

Rock drill Thor Model 28 Not Found 30 min. Likely

Although a hazard cannot be specifically determined without knowing the vibration levels of the air shovel, jackhammer, and rock drill it is very likely that a vibration hazard exists with these tools. It is common for 60 and 90 lb. Jack-hammers to have vibration levels in the neighborhood of 19 m/s2 and rock drills of 24 m/s2. Field measurements using older 60 lb. jackhammers have even been measured above 80 m/s2 (See tables in Appendix 1). In view of that, it is advisable to reduce the hand-arm vibration exposure due to the likeliness of a hazard. Several options exists to reduce the exposure: 1) Use alternative methods to break up the pavement that do not subject workers to hand-arm

46


47

vibration such as a hydraulic breaker attachment on a backhoe, 2) Use lower vibration tools, and 3) Limit the exposure time, perhaps by incorporating job rotation. Appendix 1 and Appendix 2 are provided as general guidance references listing field vibration measurements and manufacturers� declared vibration values for some demolition tools. Some reduced vibration jackhammers are listed in Appendix 2. This employer is responsible for: • Ergonomics awareness education for Gas Fitters and their supervisors • Annual review of caution zone jobs • Annual review of jackhammer lifting hazard--revisiting feasible alternatives to

reduce the hazardous lifting exposures to below the hazard level. Employees must be involved in hazard assessment and when selecting measures to reduce WMSD hazards. Other employers may use results of this job assessment as a useful comparison, but will need to determine if their own employees have similar exposures. For example, the worker for a different employer performs additional duties that contribute to the exposure but are not accounted for in the list of contributing exposure task/activities provided in this assessment, that employer needs to do its own analysis.


Maintenance Worker 2 (Waste water crew member) Sewer City of Vancouver (WA)

Job Title Type of utility Company Name

Short description of job duties: Performs regular inspection on water and wastewater lines, manholes, and sewer drain fields; operates power rodder, high velocity jet flusher, video inspection equipment, and vac-all truck. Cleans, flushes and restores these lines to operating condition. Responsible for laying and aligning pipe; installing, repairing or replacing manholes. Operates construction equipment and power tools such as: dump trucks, front-end loaders, backhoes, compressors, jackhammers, sand-blasters, concrete saws, and sewer rodders.



Caution Zone Jobs


Level?




3. Squatting NO

4. Kneeling NO






10. Heavy lifting YES Gas generator, 2� concrete grade ring, 6� concrete grade ring, 24� diameter manhole collar, manhole covers, jackhammer


12. Awkward lifting YES Lowering and lifting the camera into/out of the manholes

13. Using high vibration tools YES

Gas powered jack hammer, hydraulic jack hammer, slab saw, chain saw


Each company can use these results as a useful comparison, but will need to determine if their own employees have similar exposures. The results of this assessment reflects the job at this particular utility. These results may not be true for the same job title at a different utility.


HAZARD LEVEL ASSESSMENT A. Lifting Hazard(s): Yes�see all �YES� listings in table Table itemizes all lifts that called for the hazard level of assessment NOTE: If the same item is lifted from different positions, two or more hand zone numbers appear in the Hand Zone cell (e.g., lifting from ground level and lifting off the truck bed).

Item Lifted

Weight (in lbs.)

Frequency Factor

Twist Factor

Hand Zone(s) (Use number

from lifting calculator picture)

Is it a Hazard?

1. Gas generator 90 1 1 70 YES

90 YES 2. 2� concrete grade ring

78 1 .85

70 YES 90 YES 3. 6� concrete

grade ring 234 1 .85 70 YES 90 YES 4. 24� diameter

manhole collar 178 1 .85 70 YES

90 NO 5. 24 inch 16 hole

manhole cover

(use 2/3 of actual weight in lifting

calculator)

110 1 1

70 YES

90 YES 6. 24 inch 2 hole

manhole cover

(use 2/3 of actual weight in lifting

calculator)

155 1 1

70 YES

7. Video camera 45 1 .85 70 NO

8. Jackhammer* -on/off truck 89 1 1 90 NO

9. Jackhammer* -during use 89 0.3 1 90 YES

10. Jackhammer* -on/off truck 60 1 1 90 NO

11. Jackhammer* -during use 60 0.3 1 90 YES

*jackhammer weight includes the tip or chisel

49


HAZARD REDUCTION EXAMPLES FOR LIFTING:

Gas generator (item 1): Recommendation: Use two people to lift the gas generator.

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2� and 6� concrete grade ring (items 2 and 3): Recommendation: Use 2 people to lift the 2� concrete grade rings. For the 6� concrete ring�purchase concrete rings that come with eyebolts attached. Use an excavator or backhoe with a chain through the eyebolts to hoist the ring. Commercially available concrete housing lifters can also be used with an excavator or backhoe to lift and place heavy concrete rings.

24� diameter manhole collar (item 4): Recommendation: Use a mechanical assist such as an excavator or backhoe with a chain to hoist the manhole collar. Chains can be rigged with a lifting plate/bar or with handles (if collars have eyebolts or handles attached).

There are commercially available devices made for lifting and placing manhole collars.

50


110 lb. and 155 lb. manhole cover (items 5 and 6): Recommendation: See section on acceptable methods for lifting manhole covers. Another way that an employer (City of Vancouver) addressed this problem was to develop a tool. Crewmembers designed and developed their own tool that changes the method from a lift to a pushing down of a lever. Off-the-shelf tools that utilize this principle are available, however, they are generally limited to loads up to 250 lbs.

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Lifting jackhammers (items 9 and 11): Lifting the 89 lb. jackhammer out of the truck is not a WMSD hazard but would be if the combined jackhammer and chisel weight exceeds 90 lbs. Commonly, a worker tips the jackhammer from ground level to an upright position. Thus, the lifting weight from ground level is at maximum ½ of the total weight of the jackhammer. Once in the upright position, the worker lifts the jackhammer by the handles from about waist height. Tipping the jackhammer up from the ground is not a lifting hazard. However, a WMSD hazard exists with frequent lifting of the heavy tool during normal operation of a jackhammer. See discussion section for further details.

Recommendations: 1) Use a machine mounted hydraulic pavement breaker (on a backhoe, excavator, etc.) whenever possible. Doing so eliminates heavy lifts and hand-arm vibration exposure related to jackhammer use. 2) Use a walk-behind concrete saw to score and cut the designated area instead of using a jackhammer. Positioning this device does not involve lifting. 3) Use two people when lifting jackhammers that weigh more than 90 lbs. during equipment loading and unloading.

The following recommendations reduce lifting exposures but do not reduce exposures below the hazard level. 4) If manual jackhammering must be done, limit its use to less than 1 hr. per day and use job rotation to keep exposures below this level. 5) If a jackhammer must be used, store the jackhammer in easy to reach locations such as in a holster mounted at an angle on the compressor; storing it in an external cabinet with a low floor and a swing away door so that that it does not have to be lifted over an obstruction; or use a hinge-mounted rod or a bracket that allows the jackhammer to be tilted between horizontal to vertical positions for better positioning while loading or unloading.

Courtesy of Ira Janowitz UC San Francisco/Berkeley

Ergonomics Program

(CONTINUE TO NEXT PAGE)

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Discussion

Jackhammer Operation � Frequent Lifting of Heavy Jackhammers Utility industry assumptions: 1. Workers use jackhammers for less than 1 hr. per day 2. Hydraulic machine mounted breakers are used for large jobs and when space

affords their use. Situations remain where manual 60 lb. and 90 lb. jackhammers must be used. The maximum acceptable lifting weight is 27 lbs for the given parameters of less than 1 hr. per day, 10+ lifts per minute, and hand location close to the body between knee and waist height. This is a hazardous exposure for either jackhammer. This is still true even if the lift frequency is 8-9 per minute.

Possible options: o Explore the feasibility of using a small walk-

behind mechanical device with a hydraulic breaker attachment. Consider renting a walk-behind device with a hydraulic breaker attachment on a trial basis to determine if this is an appropriate alternative to a manual jackhammer.

o Explore the feasibility of using a rock drill

combined with a hydraulic splitter as an alternative to a manual jackhammer. The method involves drilling a series of holes along the desired cracking line and placing a splitter tool in the hole. Subsequently, the pressure build-up causes the concrete or asphalt to split along the series of holes.

o A prototype of a jackhammer lift-assist device has been made. Currently,

field tests are being conducted on it as part of a gas utility funded project (NYGAS Millennium Project M-2001-011). This is the second-generation prototype. The device is designed to push the embedded jackhammer chisel out of the concrete using an actuator. The operator mainly uses his/her hands to guide and stabilize the jackhammer rather than lift the tool, as before. The primary reason the device was designed was to reduce the force required to unseat a stuck jackhammer chisel. Coincidentally it will also address the frequent lifting problem that leads to the WMSD hazard. (NOTE: The combined weight of the jackhammer plus the device makes it heavier, however, the operator is no longer required to lift the jackhammer to reposition it during normal operation. Workers will still need to lift the jackhammer while loading it on/off the truck). The device is not available commercially at this time. Should this

52


lift-assist device become available in the future, it may effectively reduce the lifting exposure to below the hazard level. (The device was designed by Stu Senator of Dunton Design Associates, Inc.: http//dunton.senator.net)

o A third generation prototype, �RAPTOR III�, was developed to break up

pavement quietly and efficiently (Department of Energy and Brookhaven National Laboratory). The device uses a helium driven gas gun to fire a series of nails into the pavement/concrete. Raptor III is bulky and slower than a jackhammer. It would require further improvements before it could become a viable alternative. This device is not available commercially at this time.

While current practices will continue to be used, employers using this type of equipment should periodically review the availability of feasible alternatives that will reduce the lifting hazards associated with these tools.

B. Hand-Arm Vibration Hazard: Yes�see �YES� listing in table Hazard determination is based on the vibration level of each specific tool (make and model) and the length of time the tool is used. Those numbers are plotted as coordinates into the Hand-Arm Vibration graph (Appendix B of the WA Ergonomics Rule) to determine if a vibration hazard exists. If the vibration level is not available for a tool, a hazard cannot be determined. Vibrating Hand Tool

Make/Model #

Vibration Level Duration Is it a Hazard?

Jack hammer -gas powered- 60 lb.

Berema (Atlas Copco) FB60

10 m/s2

<40 min. NO

Jack hammer -hydraulic- 89 lb.

Stanley BR89

21.5 m/s2

<40 min. YES - depends on

duration Slab saw Stihl TS400 7.6 m/s2 <40 min. NO Slab saw Homelite 98D Unknown <40 min. Unable to

determine Chain saw Stihl MS310 7.5 m/s2 <40 min. NO

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There is a hand-arm vibration hazard if a worker uses the Stanley BR89 hydraulic jackhammer for 40 minutes as indicated in the graph. A hazard cannot be determined for one of the slab saws because the vibration level is not available.


54

⇒

Appendix 1 and Appendix 2 are provided as general guidance references listing field vibration measurements and manufacturers� declared vibration values for some demolition tools. Some reduced vibration jackhammers are listed in Appendix 2.

HAZARD REDUCTION EXAMPLES FOR HAND-ARM VIBRATION EXPOSURE:

Hydraulic jackhammer with a vibration level of 21.5 m/s2: Recommendations: Use the jackhammer for a shorter duration (<27 minutes) to reduce the exposure below the hazard level. This could be achieved by using job rotation to reduce the single-person exposure duration. Another way to reduce the hazard is to use a jackhammer with a lower vibration level or substitute the tool with alternative equipment with suitably less vibration.

This employer is responsible for: • Ergonomics awareness education for waste water crew members and their

supervisors • Annual review of caution zone jobs • Annual review of jackhammer lifting hazard--revisiting feasible alternatives to

reduce the hazardous lifting exposures to below the hazard level. Employees must be involved in hazard assessment and when selecting measures to reduce WMSD hazards. Other employers may use results of this maintenance worker job assessment as a useful comparison, but will need to determine if their own employees have similar exposures. For example, if a worker for a different employer performs additional duties that contribute to the exposure but are not accounted for in the list of contributing exposure task/activities provided in this assessment, that employer needs to do its own analysis.


APPENDIX 1 Field Vibration Measurements

The following table comes from a report, �GEN 503: The Measurement of Vibration Characteristics of Mining Equipment and Impact Percussive Machines and Tools� (van Niekerk, et al, 1999). See http://www.simrac.co.za/report/Reports/thrust7/gen503/gen503.htm for project summary or full report.

Vibration Levels of Commonly Used Hand-held Equipment in the South

African Mining Industry

Type of Equipment Average Maximum Weighted Acceleration

Level and Direction

Standard Deviation of the Weighted

Acceleration Level

Pneumatic rock drills

24 m/s2 (z) 14 m/s2

Hydraulic rock drills

24 m/s2 (z) 4.2 m/s2

Pavement breakers and jackhammers

19 m/s2 (z) 4.4 m/s2

Pneumatic grinders

1.3 m/s2 (x) -

Electric hammer drills

8.8 m/s2 (y) -

Pneumatic wrench

10 m/s2 (y) -

Drill sharpening machine

2.5 m/s2 (x) -

Drill re-collaring machine

5.1 m/s2 (y) -

Hand-held compactor

13 m/s2 (z) -

Data was analyzed according to ISO 5349 first edition - 1986-05-15

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http://www.simrac.co.za/report/Reports/thrust7/gen503/gen503.htm


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Field measurements taken from a 2002 NIOSH Health Hazard Evaluation Report: HETA #2001-0073-2869 Based on ISO 5349 and ANSI S3.34 (this is likely to be a typo and should instead be 19.4)


APPENDIX 2 Manufacturers� Declared Vibration Levels for Jackhammers:

Brand Model Number Weight in lbs. Vibration level

(m/s2) Atlas Copco TEX-14PS 33 14.0 Atlas Copco TEX-18PS 44 14.0 Atlas Copco TEX-27PS-118 64 14.0 Atlas Copco TEX-27PS-125 64 14.0 Atlas Copco TEX-32PS-118 75 14.0 Atlas Copco TEX-32PS-125 75 14.0 Atlas Copco TEX-39PS-118 86 15.0 Atlas Copco TEX-39PS-125 86 15.0 Atlas Copco Cobra MK-1 52.9 2.3 Chicago Pneumatic CP1210 S 54 15-17 Chicago Pneumatic CP1210 VRS 59 7 Chicago Pneumatic CP1230 S 68 15-17 Chicago Pneumatic CP1230 VRS 76 7 Chicago Pneumatic CP1240 S 86 15-17 Chicago Pneumatic CP1240 VRS 95 11 Chicago Pneumatic CP117 S 79 15-17 Ingersoll-Rand PROMAXX

MX60/60S 70 24.6

Ingersoll-Rand PROMAXX MX60F/60SF

70 19.7

Ingersoll-Rand PROMAXX MX90/90S

87 23.5

Ingersoll-Rand PROMAXX MX90F/90SF

87 20.6

Ingersoll-Rand JX35 32 30.2 Ingersoll-Rand JX35S 34 30.2 Ingersoll-Rand IR30VRD 33 2.76 Ingersoll-Rand IR30VRC 33 2.76 Ingersoll-Rand IR45VRC 46 4.09 Ingersoll-Rand IR45VRA 46 4.09 Ingersoll-Rand IR45VRB 46 4.09 Ingersoll-Rand IR60VRA 60 4.28 Ingersoll-Rand IR60VRB 60 4.28 Ingersoll-Rand IR90VRA 88 7.94 Ingersoll-Rand IR90VRB 88 7.94 Macdonald Air Tools VRS2 58 3.4 Racine (hydraulic) HBR-60LV 60 5.38

Shaded cells indicate lower vibration level tools

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APPENDIX 2 Manufacturers� Declared Vibration Levels for Jackhammers (continued):


(m/s2) Stanley (hydraulic) BR87 21.5 Stanley (hydraulic) BR89 21.5

Rock Drills Manufacturers� Declared Vibration Levels for Rock Drills


(m/s2) Chicago Pneumatic

CP0009 9 12

Chicago Pneumatic

CP0014RR 15 14

Chicago Pneumatic

CP0022 28 22

Chicago Pneumatic

CP0032A 55 22

Chicago Pneumatic

CP0069 60 22

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